1. Technical Field
The present invention relates to line position calculating methods, correction value obtaining methods, and storage media having a program stored thereon.
2. Related Art
Inkjet printers are known as recording apparatuses in which a medium (such as paper or cloth for example) is transported in a transport direction and recording is carried out on the medium by a head. In such a recording apparatus, when a transport error occurs while transporting the medium, the head cannot record on a correct position on the medium. In particular, with inkjet printers, when ink droplets do not land in the correct position on the medium, there is a risk that white streaks or black streaks will occur in the printed image and image quality deteriorates.
Accordingly, methods are proposed for correcting transport amounts of the medium. For example, in JP-A-5-96796 it is proposed that a test pattern is printed and the test pattern is read, and correction values are calculated based on a reading result such that when an image is to be recorded, the transport amounts are corrected based on the calculated values.
JP-A-5-96796 gives no description concerning what kind of processing is performed on the image data after the test pattern has been read. However, when dirt has adhered to the test pattern or there is a missing dot or the like, defective pixels are produced in the image data and as a result accurate correction values may not be able to be calculated.